PB1807: THE SIGNIFICANCE OF MOLECULAR RISK FACTORS IN ACUTE MYELOID LEUKEMIA
Authors: Alla Gordienko, Nadiya Goryainova, Галина Стародуб, Nataliia Tretiak, Hanna Bortnik
Journal: HemaSphere (2023)

Topic: 3. Acute myeloid leukemia - Biology & Translational Research Background: The CD28/B7 family of molecules (B7.1/CD80, B7.2/CD86) are dominant functional structures that regulate antitumor antigen-specific immune responses. Analysis of their expression concerning the acute myeloid leukemia (AML) course is of great interest. Aims: The study aims to investigate the intensity of expression of the CD28 receptor on CD3+ T-lymphocytes and CD80 and CD86 molecules on a clone of tumor cells and monocytes in patients with AML in different periods of the disease. Methods: The co-expression of CD80 and CD86 molecules by tumor cells with CD34+, CD117+, CD33+ immunophenotype and CD28 ligand by CD3+ T-lymphocytes was assessed by the method of flow laser cytometry (FACScan, Becton Dickinson). Results: Immunological studies were conducted on 28 patients with AML before and after treatment. In 1 group of patients (n=12, 42.9%) with AML in the first acute period, the total number of tumor cells in the peripheral blood (PB) with a high level of intensity of expression of the CD80bright molecule was on average 6.7±0.3%, CD86bright molecules averaged 21.0±1.1%. A low level of expression of the CD80low molecule was detected on average in 1.3±0.1%, and the CD86low molecule in 7.7±0.5% of tumor cells. The mean number of CD3+CD28+ T-lymphocytes in the blood was 27.9±1.7%. In the 2nd group of patients with AML in the first acute period (n=16, 57.1%), the total number of tumor cells with a high level of intensity of the CD80bright molecule was at an average of 1.9±0.1%, and the CD86brigt molecule was 6.0± 0.4%. A low level of expression of the CD80low molecule was detected on average in 8.2±0.2%, and the CD86low molecule in 20.3±1.2% of tumor cells. The content of CD3+CD28+ T-lymphocytes in the PB was on average equal to 23.5 ±1.3%. It was established that in patients in group 1, the number of CD80low tumor cells was 6.3 times (p<0.05) and CD86low was 2.6 times (p<0.05) significantly lower than the same indicators in group 2. But the amount of CD80bright and CD86bright respectively considerably increased by 3.7 times (p<0.05) and 3.5 times (p<0.05) than in the 2nd group of patients. In the 1st group of patients, the total number of CD3+CD28+ T-lymphocytes in PB was on average significantly increased by 1.5 times (p<0.05) compared with the patients of the 2nd group. Patients from the first group (n=12), which had higher average number of tumor cells with a high level of intensity of expression of costimulatory molecules CD80+bright, CD86+bright and CD3+CD28+bright T-lymphocytes, achieved remission. In patients with remission, a low level of intensity of expression of the CD80low molecule was found on average in 0.4±0.1% of monocytes, and a higher level of CD80bright in 41.9±1.3% of cells. On average, CD86low was detected in 3.7±0.1% of cells, and CD86bright in 7.2±3.0%; the number of CD3+CD28+ T-lymphocytes was equal to 30.1±1.5% on average. Thus, patients with AML from the second group did not achieve remission after therapy. We observed it against the background of suppression of antitumor immunity due to a low intensity of expression by tumor cells of costimulatory molecules of the B7 family and CD28+ ligand T-lymphocytes. Summary/Conclusion: The obtained data is important for the development of additional biological criteria for predicting the development of relapse and the duration of remission. Keywords: Acute myeloid leukemia